迭代重建技术在HRCT低剂量下诊断肺磨玻璃密度结节的可行性应用

摘要

目的 评价不同水平的iDose4迭代重建技术在HRCT低剂量的条件下诊断肺磨玻璃密度结节(pGGN)的可行性.方法 选择2014年10月1日～2016年4月1日在平湖市中医院行常规胸部CT检查并确诊为pGGN的患者40例,应用16排螺旋CT,设置4种不同的剂量条件(管电压120 kV;管电流100、50、25、10 mAs)对40个5～13 mm的pGGN进行HRCT检查,分别应用iDose4迭代重建技术和传统的滤波反投影(FBP)对数据进行重建,并且有两名有丰富经验的医师进行对不同剂量水平和不同重建技术的影像进行评估,同时利用Kappa分析进行一致性评价以及测量每次检查的图像噪声(MSD)、有效辐射量(ED).结果 不同管电流和图像重建技术的条件下SD值比较,差别有统计学意义(P＜0.05);相同管电流条件下和不同重建技术的条件下SD值比较,差异有统计学意义(P＜0.05);在不同管电流和图像重建技术下肺实质CT值比较,差异无统计学意义(P＞0.05);两名医师对图像质量的评分,Kappa=0.601,P=0.000,一致性尚可;应用传统的FBP及iDose4技术,100 mAs对pGGN的可见度在4分等级上显著高于50、25、10 mAs,差别有统计学意义(P＜0.05);在50、25、10 mAs条件下,iDose4-4/7重建技术在高评分上显示结节的数量显著高于传统的FBP重建技术,差异有统计学意义(P＜0.05).结论 应用16排螺旋CT能够在10 mAs的条件下检查出pGGN,联合iDose4迭代重建技术可以保证图像并且满足临床诊断需求,同时可以进一步减少对患者的辐射剂量,在早期肺癌筛查中值得临床推广.%Objective To evaluate the feasibility of diagnosing pulmonary grinded glass nodule (pGGN) by different levels of iDose4 iterative reconstruction technology under low HRCT conditions.Methods Selected 40 cases of patients who was diagnosed as a glass-polluted nodule by conventional chest CT examination in Traditional Chinese Medicine Hospital of Pinghu City,from October 1 2014 to April 1 2016.16-slice spiral CT was performed on 40 pulmonary nodular nodules whose diameter were 5 to 13 mm,took four different dose conditions (tube voltage 120 kV;tube current 100,50,25,10 mAs),reconstructed all the data by iDose4 iteration reconstruction techniques and traditional filtered backprojection (FBP).Two experienced physicians were asked to evaluate images at different dose levels and different reconstruction techniques.Consistency assessment was conducted by Kappa analysis,and the image noise (MSD) and effective radiation dose (ED) was measured for each examination.Results The difference was statistically significant (P ＜ 0.05) in SD values under different tube currents and image reconstruction techniques.The difference was statistically significant (P ＜ 0.05) in SD values under the same tube current conditions and different reconstruction techniques.There was no significant difference(P ＞ 0.05) in CT values of lung parenchyma under different tube currents and image reconstruction techniques.The consistency was good (Kappa=0.601,P =0.000) between the two doctors,under traditional FBP and iDose4 technology,there was a statistically significant difference (P ＜ 0.05) in the comparison of the visibility of pGGN at 100,50,25,10 mAs.Under the condition of 50,25,10 mAs,there was a statistically significant difference (P ＜ 0.05) in the number of nodules on the high score under the iDose4-4/7 reconstruction technique.Conclsion 16-slice spiral CT can be used to detect lung-dense glass nodules at 10 mAs,it can ensure images in the clinical combine with iDose4 iterative reconstruction technology.The radiation dose to the patient can be further reduced,and it is worthy of clinical promotion in early lung cancer screening.